Underfeed stoker



ME/mew W. A. HARE.

UNDERFEED STOKER.

APPLICATION FILED DEC. 7, 1918.

Patented Dec. 14, 1920.

4 SHEETS-SHEET I.

SJ vvue ntoz W. A. HARE.

UNDERFEED STOKER.

APPLICATION FILED mac. 7, 191a.

1,361,98&

Patented Dec. 14, 1920.

4 SHEETSSHEET 3.

3 mm: mto'z 'WILFRED AL HARE, 015: DETROIT, MICHIGAN.

UmRFEED s'roxm,

T all whom it may concern:

Be it known that I, WiLFRED A. Hams, a. subject of the King of England, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Underfeed' Stokers, of which the following is a specification, reference being had therein to the accompany.

ing drawings.

The present invention relates to improvements in boiler furnaces and more particularly to furnaces of the underfeed type having a retort and inclined grate bars with one end supported adjacent the retort. The object of the invention is to provide certain new and useful features in the construction and arrangement of parts whereby a more positive feeding of fuel is secured, a better distribution of air is provided and parts prevented thereby from being burned out, a new and beneficial construction and operation of grate bars obtained, and an eflicient ash and clinker discharge provided.

With these and other ends in view, the in vention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims, reference being had to the accompanying drawings, 1 n wh1cl 1- Figure 1 is a longitudinal vertical section through a furnace embodying features of the invention;

Fig. 2 is a transverse vertical section through the same;

Fig. 3 is a sectional view similar to Fig. 2 illustrative of the operation of grate bars and dumping grate;

Fig. 4 is a front elevation of the furnace with parts shown in section substantially upon the line IVIV of Fig. 1

Fig. '5 is a front end elevation of grate bars and dumping grate, showing operating mechanism therefor and a retort and pusher in section substantially upon the line VV of Fig. 1;

Fig. 6 is a sectional detail through a portion of the front end portion of a retort and hopper throat;

Fig. 7 is a detail showing a twyer block in elevation;

Fig. 8' is a similar detail of a twyer block of-the opposite twyer; I

-Fig. 9 is a detail showing a series of grate bars in end elevation with a twyer block in section; and

Figs. 10, 11, 12 and 13 are perspective views of twyer-block sections.

' Specification of Letters Patent. t t 14, 1920 Application filed December 7, 1918.

Serial N0. 265,698.

While a construction of furnace is shown in which a retort is located adjacent one wall of the furnace with grate bars extending laterally from one side of the retort, it will be understood that such arrangement is merely illustrative of the invention which may be embodied as well in a furnace having a duplicate set of grate bars and mechanism at the other side of the retort, and fur-- ther changes in the construction and arrangement of parts may be made within the scope of the appended claims.

As shown in the drawings, 1 is a suitablefeed box bolted or otherwise secured to the front plate 2 of the front wall of the furnace and forming a continuation of the retort 3 which has a throat or' extension 1 opening through said wall.- The feed box 1 has an opening in its upper side forming the throat 5 of a hopper 6 and secured to and closing the front end of the feed box is a casing 7 forming a steam cylinder and chest, within which cylinder is a piston 8 operated in the usual manner by steam or other fluid pressure admitted through inlet ports and passages in the chest. A suitable piston rod 9 is operated by the piston, and this rod is connected in any suitable manner to the forward end of a pusher slide 10 which forms a movable bottom for the retort 3. Obviously, any suitable power device may be connected to the pusher slide 10 for reciprocating the same upon supporting ribs 11 provided therefor upon the feed box and the side walls 12 of the retort.

The forward end of the slide 10 is formed with a pusher head 13 providing a reciprocable pusher table 14 of a length to close the throat of the hopper when the slide is in its rearmost position and a vertical pusher wall 15 behind which the coal from the hop per falls when the slide moves forwardly, the head 13 having the table 14 and wall 15 forming a reciprocable pusher. This table has upwardly projecting edge ribs 16 formed with inclined inner sides forming a continuation of the inner inclined faces of the throat 5, which faces are slightly undercut to receive these ribs, the joint between the table and side walls of the throat being thus formed above the upper face of the table to prevent the joint from becoming clogged and to assist in preventing fine coal and dust from passing therethrough. To prevent fine coal and dirt from passing through the joint between the upper face of the table at its throat is recessed to receive a block 17 which fits loosely in the recess and rests upon the face of the table. Close contact of the block with the table is maintained by gravity as the table slides back and forth beneath the hopper throat and thus fine particles of coal are prevented from working through the joint at the forward end of the table, the block acting as a gravity scraper.

To provide a non-reciprocable plate or table to receive the coal as it falls from the hopper behind the pusher wall 15, said wall is provided with a slot or opening 15 centrally disposed and adjacent the upper face of the pusher slide 10 and of a length equal to the width of said face. Projecting through this slot is a plate or gravity table 18 pivotally supported at 19 forwardly of the path of movement of the pusher and provided with a downturned rear end or rib 20 to engage the upper surface of the pusher slide 10, said. plate being of a length to ex tend inwardly beyond the throat of the hopper with its-inner end held by gravity in contact with the face of the slide. To close the slot in the wall 15 so that fine particles of coal can not work through above the plate 18, a plate or block 21 is loosely attached to the rear side of the wall 15 by means of a bolt 22 passing through a vertically elongated slot in the plate with the lower edge of said plate held by gravity in contact with the upper surface of the plate 18. The joints between the reciprocable pusher and adjacent non-reciprocable parts are thus closed to prevent fine coal and dust from sifting through and clogging of the pusher is prevented so that it will always slide freely. The plate 18 also provides a nonreciprocable table to receive coal from the hopper and from which it is pushed rear- Wardly into the retort by the pusher, the coal fed in being thus prevented from being dragged back beneath the hopper by a return or forward movement of the pusher slide, and the danger of clogging being eliminated due to the fact that said plate 18 is pivotally supported at its forward end so-that the weight of coal falling thereon holds its rear end in firm contact with the surfaces of the pusher slide.

It is common practice to set the pusher slide and retort at a slight inclination in the direction of its length to a horizontal plane so that the coal will feed into and along the retort more readily but such construction has certain structural and manufacturing disadvantages which are overcome in the present construction by forming the upper surface of the pusher slide 10 in a plane which is inclined in the direction of the length of the slide, to its plane of reciprocation which is horizontal, and such construction is permissible as the receiving plate Walls of the furnace, said walls 23 and 24 forming a wind box 25 into which air under pressure is admitted through a suitable conduit 26, and its admission is controlled by a suitable shutter or damper 27 of any desired form which may be operated by means of a push rod 28 extending through the furnace front and provided with a hand hold for convenient manipulation by the attendant.

The upper ends of the walls 23 are each provided with an outwardly projecting flange 29 forming seats for twyers 30 and 31 which rest thereon and the upper edges of the retort walls 12, spanning the space between said walls and the walls 23 of the Wind box from the front to the, back walls of the furnace. In the construction shown, this flange 29 of one of the walls also forms a seat for the upper ends of a series of hollow grate bars 32 and 32, the other wall of the wind box being located adjacent a side wall 33 of the furnace, but it will be understood that in furnaces having a double setof grate bars, the wind box may be located at the center of the furnace chamber with llke twyers and sets of grate bars seated upon said flanges 29. With the wind box located as shown, the twyer 31 forms means for conducting air tothe retort at one side for maintaining combustion and for cooling the twyer, said twyer comprising a wall plate 31 and a twyer block 35, said block being formed of a plurality of sections 36 and 37 secured together by bolts or rivets 38, there being a plurality of the sections 36 placed face to face between two end sections 37 to form a block. Each section 36 has ribs 39 projecting laterally from a central rib or web 40 and a face portion 41 the full width of the section, said face portions together forming a continuous twyer wall' when the sections are secured together, the ribs 39 on one section meeting the adjacent sections to form air passages 42 openin through the face portion orwall 41. The ribs 39' extend inwardly and curve upwardly within and toward the top of the wall plate 34, so that air from the wind box is forced to ascend to the top of the twyer before it can enter the passages-42 and pass out into the retort through these passages which open through the wall 41 of the t wyer, thus cooling the upper end of the twyer block and wall-plate. The end sections 37 of each twyer block are also provided with ribs 39 forming, together with the ribs of adjacent sections 36, passages 42,

and these end sections are also providedwith hooks 43 at their upper ends and hooks 44 at their lower ends, these hooks being provided to engage rounded projections 45 and 46 on the wall plate 34 and retort wall 12, respectively. When the several sections forming each block 35 are secured together by bolts 38, said blocks are set into place upon the retort walls 12 and the hooks 43 engaged over the projections 45 on the wall plate. The blocks are thus detachably held in place so that they may be quickly and easily lifted out for replacement and repair, but are firmly held in place for use by their hooks, .any movement of the lower ends of the blocks toward the wall plate being prevented by lugs 47 on the end sections 37 which lugs are provided to engage corresponding lugs or projections 48 on the wall plate. These blocks 35 are thus made up in sections to facilitate manufacture and are formed to interlock with the wall plate and retort wall in such a manner that they will not become displaced in use but arealways readily detachable for replacement or repair.

In a similar manner, the twyer 30 is made up of a series of blocks 49 and each block comprises a series of intermediate sections 50 and end sections 51, which sections are secured together by bolts or rivets 52. The several sections are provided with laterally extending ribs 53 which, when the sections are secured together meet adjacent sections and form air passages 54 which open through the face wall 55 of the twyer block. lhis face wall-is extended upward and outward forming a projecting portion 56. adapted to overlie the upper ends of the grate bars 32 and 32*. The end sections 51 are each formed with a vertical wall or web 57 having a lug 58 at the lower end thereof projecting inwardly of the block to underlie the ends ofthe grate bars and said end sections are also formed with hooks 59 to engage rounded projections 60 on the wall 12 of the retort, similar to the hook 44 and projection 46 of the twyer blocks 35 and retort wall, respectively. The twyer blocks 49 are thus formed to rest upon the flange 29 of the wall of the wind box, and the adjacent wall of the retort, spanning the space between said walls and forming air passages therethrough connecting the wind box and the upper ends of the several hollow grate bars, the several passages 54 in the twyer block forming conduits communicating with said passages and opening into the retort. An unobstructed passage is thus provided by the several twyer blocks for conducting air into the grate bars and both twyer and grate bars are effectually cooled thereby and prevented from burning out.

The series of grate bars is made of fixed and movable bars alternating either individually or in pairs each having substantially the same construction with the exception that the fixed bars 32 are provided with lugs 61 near their lower ends to engage a rib 62 on a suitable-fixed supporting wall 63, which wall with the adjacent side wall 23 of the wind box, forms a closed air chamber 64 beneath the grate bars. The movable bars 32 are each provided with a socket at its lower end to receive a longitudinal rib 65 on a rocker-bar 65 supported in a suit- I able bearing on the side of the wall 63. The grate bars are each rectangular in cross section being preferably formed of two channel members bolted together to form a hollow bar which is open at its upper end and closed at its lower end, an outlet opening 66 being provided at the lower side of each bar near its lower end to connect the passage through each bar with the chamber 64 so that air under pressure from the wind box 25 will circulate through the twyer 30 and the hollow grate bars 32 and 32 to the chamber 64 and from thence upward between the grate bars to .maintain combustion of the coal thereon. To cause a portion of the air to to receive the ash and clinker therefrom and this grate is formed of a series of movable sections pivotally attached to and supported at their upper ends by cars 69 on the rocker bar 65. The lower ends of the grate sections are carried by links 7 O pivotally connected to the sections at one end and to arms 71 at their opposite ends, which arms are secured upon a shaft 72 mounted in suitable bearings on the supporting wall 63. The outer end of the shaft 72 extends through the frorgt wall and front plate 2 of the furnace and is provided with a sector 73 engaged by a worm 74 mounted in a suitable bracket 75 on said plate and forming a bearing for an operating shaft 76 which extends past the side wall of the furnace and has a formed end 77 for the engagement of an operating crank (not shown) by means of which the shaft and worm may be turned to turn the shaft 72 and thus swing the grate members 68 about their pivotal support on the rocker bar 65.

The size of the opening or space between i the. end of the grate and the side wall 7 8 of the furnace may thus be adjusted or the grate swung down to the position shown in dotted lines in Fig. 3 for the purpose of dumping the ash and clinker-s.

Mounted in the inner side of the wall 78 is a suitable bracket or support 79 forming a bearing for a shaft 80 upon which is mounted a series of toothed wheels 81 loosely mounted'on the shaft to turn freely thereon and form a clinker bar or crusher. The grate members 68 are continuously operated by the rocking movement of the rocker shaft 65 by which they are carried and thus a reciprocating motion toward and from the crusher S1 is imparted to the grate which works the ash and clinker downwardly thereon and through the space between the downwardly curved lower ends of the grate sections and the clinker bar. By reason of the support of the grate sections at their lower ends by the links 70, these sections have an outward and downward movement toward the clinker bar so that any clinker caught between said clinker bar and downwardly curved ends of said grate members will be crushed by such movement, and the toothed members 81 being free to turn on their shaft will assist in such crushing action and at the same time will be turned thereby so that a different portion of their surface will be presented to extreme heat above the grates, thus preventing the burning out of the .clinker grinders or members 81. These clinker grinders also take the wear which would otherwise disintegrate the furnace wall and the continued reciprocation of the ash grate, prevents the accumulation of hot ash and clinker, without attention on the part of the operator.

Motion is imparted to the rockershaft 65 from the pusher slide 10 by means of a rocker 82 pivotally mounted intermediate its ends upon a suitable fixed bracket 83 secured to a side wall of the retort, one end of said rocker being connected by a link 84 to the pusher slide, and the other end of said rocker being connected to an arm 86 on the end of the shaft 65, by a connecting rod 87, all as shown in Fig. 5.

As the pusher is reciprocated by the piston 8 to feed coal into the-retort, this reciprocation imparts a rocking movement to the rocker 82 and it in turn, through its connecting rod 87, imparts a swinging movement to the arm 86, rocking the rockshaft 65 back and forth continuously, which movement raises and lowers the movable grate bars 32 'by reason of the engagement of the rib 65* on the rock-bar with the sockets therefor on the bars, and also continuously reciprocates the ash grate members 68. As the movable grate bars 32 are carried at their lower ends by the rocker-bar 65 and rest upon the flanged upper end of the wall '23 of the wind box, free to slide thereon,

these movable grate bars are not only raised and lowered by the turning of the rockerbar 65 but a limited reciprocating movement is imparted thereto which movement greatly assists in spreading and working the coal down uponthegrate and in preventing the clogging of the air passages between the grate bars. As the movable grate bars are independent of the twyer 30, said twyer remains stationary upon the retort so that the coal therein is not disturbed and the twyer forms a smooth continuation of the retort wall over which the coal passes freely. By continuing the wall 55 of the twyer sections to overlie and bear upon the ends of the grate bars by gravity, fine coal is prevented from working into the spaces between the ends of the bars and the twyer and hindering free movement of the bars or clogging the passages, and the upper ends of the bars are covered thereby to protect the same from the heat and present a smooth rounded surface.

Obviously, changes may be made within the scope of the appended claims, in the form, construction and arrangement of parts without departing from the spirit of the invention and I do not therefore limit myself to the particular embodiment shown. 90

\Vhat I claim is:

"1. In a furnace stoker, the combination of a pusher for feeding fuel into the furnace, means for reciprocating said pusher,

a hopper, a non-reciprocable gravity table beneath the hopper to receive fuel therefrom, and from which table the fuel is forced by the reciprocation of the pusher thereover, and apusher slide reciprocable with the pusher and in contact with which the table is held by gravity.

2. In a furnace stoker, the combination of a pusher slide extending into the furnace,

a pusher head on the slide having an opening disposed centrally of the slide, a hopper beneath which the head is reciprocable,'a non-reciprocable gravity table extending longitudinally of the slide through said opening with its inner end portion only held by gravity in contact with-the upper surface of the slide, and means for reciprocating the slide and head.

3. In a furnace stoker, the combination of a pusher slide, extending into the furnace,

a pusher head, a hopper beneath which the head is reciprocable, a gravity table pivotally supportsd independent of said slide and head and extending beneath the hopper with its free end held in contact with the slide by gravity, and means for reciprocating the slide and head.

4. In a furnace stoker, the combination of a pusher slide extending into the furnace and having a pusher head with an opening between the slide and head, a non-reciprocable pivotally supported tableextending longitudinally of the slide through said opening with its free end held by gravity in contact with the upper face of the slide, and means for reciprocating the slide.

Matt

5. In a furnace stoker, the combination of a hopper, a pusher slide extendmg into the furnace and provided with a head reciprocable with the slide beneath the hopper,-

ing upon the upper surface of said slide, and

means for reciprocating the slide.

6. In a furnace stoker, the combination of a hopper, a pusher slide extending into the furnace and provided with a head reciprocable with the slide beneath the hopper, said slide having an opening adjacent the head, a table pivotally supported at one end independently of the slide and extending longitudinally of the slide through said opening with its free end restlng upon said slide, and a member beneath the head. held by gravity upon the upper surface of the table to close the opening between the head and the upper side of the table.

7. In a furnace stoker, the combination of a hopper, a pusher reciprocable beneath the hopper and having a member provided with a plane upper surface to close the throat of the hopper, and a member at one side of the throat and free to move toward and from said plane upper surface and held by, gravity in contact with said surface to close the space between said pusher member andhopper throat.

8. In a furnace Stoker, the combination of a hopper, a pusher slide extending into the furnace, a head on the outer end of the slide providing a horizontal closure for the hopper and a vertically extending wall between the closure and slide, said wall being formed with a slot adjacent the slide, a table pivotally supported at one end with its free end extending through the opening in said wall and resting upon said slide, a closure for said slot carried by the outer side of said wall and held in engagement with the upper surface of the table by gravity, a vertically guided gravity block extending across in contact with the upper surface of the head forming the closure for the hopper and at the forward side of the throat of the'hopper, and means for reciprocating the pusher slide and head.

9. In a furnace stoker, a reciprocable pusher slide having an upper surface inclined in the direction of its length throughout the major portionthereof to its plane of reciprocation to provide an inclined coal carrying surface, and means for reciprocating the pusher slide.

10. In a furnace stoker, a horizontally reciprocable pusher slide extending into the furnace and having an upper fuel carrying surface throughout that portion thereof which extends into the furnace, which surface is inclined downwardly toward its inner end in the direction of the length of the slide, and means for reciprocating said pusher slide.

11. In a furnace stoker, the combination of a retort having an extension projecting through a wall of the furnace, 'a hopper mounted upon the extension and formed with a throat having vertical guides at the forward side thereof, a gravity block in said guides forming the forward side of said throat, a pusher slide forming the bottom of the retort and having an upper surface inclined in the direction of its length to its plane of reciprocation, a head on the outer end of said pusher slide forming a closure for the hopper throat and upon which the gravity block rests, said head having an opening adjacent the upper surface of the slide, a member pivoted within the extension and extending through said opening with its inner end resting upon the upper surface of the slide, and means for reciprocating the slide and head.

12. In a furnace, the combination of a retort having a side wall, a series of hollow grate bars supported at one end adjacent to said wall, and a twyer upon said wall formed of a plurality of detachable blocks into which the open ends of said grate bars open, said twyer blocks being formed with portions to overlie and portions to under 1e said ends of said bars, whereby the twyer blocks are detachably interlocked with the bars and held in place thereby.

13-. In a furnace, the combination of a retort having a side wall, a series ofhollow inclined grate bars supported at their upper ends adjacent said wall and free to move relatively thereto, a hollow stationary twyer on said wall inclosing and detachably interlocked with the open upper ends of said bars, and a rocker bar adjacent the lower ends of the grate bars for imparting thereto a rising and falling movement at their lower ends and a sliding movement at their upper ends within said twyer.

14:. In a furnace, the combination of a wind box having side walls, a retort in the upper portion of said box, with its side wall spaced from the side wall of the wind box, a twyer spanning the space between said side wall of the box and said side wall of the retort, a' series of hollow inclined grate end of said bars upon which they are free to move, a retort having a side wall, a twyer formed to detachably engage the retort wall and support and span the space'between said wall and support, said twyer being formed with portions to overlie and-portions to underlie the ends of said grate bars, and means for imparting movement to said bars.

16. In a furnace, the combination of a series of hollow grate bars, a support for one end of said bars upon which they are free to move, a retort having -a side wall spaced from said support, and a twyer detachably interlocked with said side wall of said retort and spanning the space between the retort and support and overlying and resting by gravity upon the ends of said grate bars upon said support, and means for imparting movement to said grate bars.

17. In a furnace, the combination of a series of hollow grate bars, a support for one end of said bars upon which they are free to move, a retort having a side wall, and a twyer formed with a wall forming a continuation of the retort wall and having openings therein, said twyer being formed of a plurality of sections each having ribs meeting the adjacent sections to form air passages leading to said openings in the wall of said twyer, certain of saidsections beingforined with means to detachably engage the retort wall and with portions to underlie said grate bars, said sections together forming a curved passage connecting the open ends of the grate bars with the space below the twyer.

18. In a furnace, the combination of a series of hollow grate bars, a support for one end of said bars upon which they are free to move, a retort having a side wall spaced from said support, and a twyer formed of a plurality of independently detachable blocks free to move rotatively upon said retort wall and having projections to interlock with said wall, said twyer blocks each being also formed with a portion to overlie and to be held by gravity in contact with the upper surfaces of said ends of said bars, and means for imparting movement to said gratebars.

' 19. In a furnace, the combination of a furnace wall, a retort extending parallel with and spaced from said wall, a twyer forming a continuation of the side wall of the retort and having projections to detachably engage said retort wall, and a member secured to the furnace wall and having projections to 'detachably. interlock with projections on said twyer.

20. In a furnace, the combination ofa furnace wall, a retort having a wall extending parallel with and spacedfrom said furnace wall, a hollow twyer spanning the space between said furnace wall and said wall of said retort and comprising a member secured to the furnace wall and a series of hollow twyer sections formed to detachably interlock with said member and with the adjacent wall of the retort to span the space therebetween and form an upward continua:

lock with the wall member and the adjacent wall of the retort, each section being formed with ribs to meet the adjacent sections and form air passages opening through the wall of the twyer and extending upwardly within the twyer.

22. In a furnace, the combination of a furnace wall, a retort extending parallel with and spaced from said wall, a hollow twyer spanning the space between said furnace wall and said retort and comprising a member secured to said wall and a series of blocks each-formed with a wall forming a continuation of a wall of the retort and provided with means at one side adapted to interlock with the wall member and with means at the other side adapted to engage the adjacent wall of the retort, each block being also formed with 'air passages open between said wall member and retort wall and detachably interlocked with said member and wall, a series of hollow grate bars supported at one end by a wall of the wind box, a twyer spanning the space between said ends of said grate bars and the adjacent wall of the retort, said twyer being formed .with a passage connecting the space between said wind box wall and retort with the open ends of said grate bars, and with an upwardly extending and outwardly curved wall forming a continuation of the retort wall and having twyer openings opening into said passage, and said twyer wall being extended over and resting by gravity upon the upper ends of said bars with said 1 ends extending into said twyer and free to move longitudinally relatively thereto, said twyer being also formed with portions series of inclined grate bars, a rocker bar adjacent the lower ends of said bars for operating the same, an ash grate supported at one end by and connected to said rocker bar to lee-operated thereby, and means for supporting the opposite end of said ash grate adapted to permit actuation of the ash grate by said rockerbar.

25. In a furnace, the combination of a series of inclined grate bars, a rocker bar for operating said bars and supporting their lower ends, an ash grate at the lower end of said bars to receive ash and clinker-s therefrom and supported at one end and moved by said rocker bar, and means for supporting the opposite end of said ash grate adapted to cause a downward movement of said end as said grate is reciprocated by said rocker bar.

' 26. In a furnace, the combination of a series of inclined grate bars, an ash grate at the lower ends of said bars to receive ash and clinker therefrom, a rocker bar for supporting and operating the lower ends of the grate bars and one end of the ash grate, and pivotal means for supporting the opposite end of the ash grate.

27. In a furnace, the combination of a series of inclined grate bars, an ash grate at the lower ends of said bars to receive ash and clinker therefrom, a rocker bar for supporting and operating the lower ends of the grate bars and one end of the ash grate, and links pivotally connected to said ash grate for supporting the opposite end thereof and adapted to permit a rising and falling movement thereof.

28. In a furnace, the combination of a series of inclined grate bars, an ash grate at the lower ends of said bars to receive ash and clinker therefrom, a rocker bar for supporting and operating the lower ends of the grate bars and one end of the ash grate, a link pivotally attached at one end to said ash grate for supporting the same at its free end, a pivoted arm connected to the opposite end ofsaid link, and manually oper able means for turning said arm.

29. In a furnace, the combination of a series of inclined grate bars, an ash grate at the lower end of said bars to receive ash and clinker therefrom, a rocker bar having a longitudinal rib engaging the grate bars to operate the same, ears on the rocker bar to which the ash grate is pivotally attached at one end to be supported and actuated thereby, and means for pivotally support+ ing the opposite end of said ash grate.

30. In a furnace, the combination of a series of inclined grate bars, an ash grate at the lower end of said bars to receive ash and clinker therefrom, a rocker bar having a longitudinal rib engaging the grate bars to operate the same, ears on the rocker bar to which the ash grate is pivotally attached at one end to be supported and actuated thereby, a shaft, an arm on said shaft extending beneath the ash grate, a link connecting the end of said arm and the opposite end of said ash grate to pivotally support the same, means for manually turning said shaft and power operated means for turning the rocker shaft.

31. In a furnace, the combination of a series of hollow inclined grate bars having open upper ends and each having an opening in its lowervside near its lower end, a deflector in each bar opposite each opening in the lower side thereto to deflect air passing through the bar, into the end portion of the bar, a wind box having a wall forming a support for the upper ends of said grate bars, an air chamber below the grate bars'into which the openings near the lower ends of said bars open, a stationary twyer inclosing the upper open ends of the grate bars and forming a passage connecting said ends directly with the wind box, and means for operating the grate bars.

, 32. In a furnace, the combination of a retort extending int said furnace, and a twyer detachably engaged with a side wall of said retort and comprising a plurality of sections having laterally projecting portions to provide air passages between thesaid sections, said passages leading to the side of the twyer forming a continuation of said retort wall, and a plurality of hollow grate bars movably supported with their ends opening into said twyer.

33. In a furnace, a twyer formed of a series of blocks comprising a plurality of vertically extending sections secured together, each section having a wall formed with openings, a Web extending inwardly from said wall, and ribs on the web adapted to meet adjacent sections and form air passages between the sections leading to said openings, a series of hollow grate bars supported with their upper ends opening into and movable within said twyer, and

means for imparting motion to said grate bars.

In testimony whereof I affix my signature in the presence of two witnesses.

WILFRED A. HARE.

Witnesses:

ANNA M. Donn, CHAS. W. STAUFFIGER. 

